Adjustable drawbar



Allg. 22, v E H ALLEN Er AL ADJUSTABLE DRAWBAR Filed DeC. 9, 1932 2 Sheets-Sheet l Aug. 22, 1933. E. H. ALLEN ET AL ADJUSTABLE DRAWBAR Filed D ec:.`9I 1932 2 Sheets-Sheet 2 Patented Aug. 22, 1933 Y l y Urrea stares PATENT orifice 1,923,964 ADJUSTABLE DnAwBAn Edwin H. Allen and vGeorge H. Connors, Edgerton, '.Wis., assignors to Highway Trailer Company,

Edgerton, Wis.,'a Corporation of Wisconsin Application December 9, 1932. `Serial No.6l697 Y s claims. (cl. 2st-earn) The present invention 'relates to a draw bar present invention provides a draw bar structure structure for road vehicles such as trailers, and in which the effective length thereof may be quickhas for itsA rnain object toprovide an improved ly and' easily adjusted to a plurality of Vpositions construction which permits of quick and easy to increase its length, to alord adequate clear- 5 longitudinal adjustment of the draw bar in a ance between the bodies of the adjacent vehicles, 60 plurality of positions, for varying its effective and, likewise, the draw bar may be quickly relength. Another object is to provide a novel duced in length when the vehicle train is again construction adapted, when adjusted, to autobrought onto the highways. matically lock the draw bar in its various posi- Referring now in detail to the drawings: The

Vlo tions of longitudinal adjustment. A still furstructure embodying this invention consists of 65 ther object of this invention resides in the `proa draw bar member indicated at 10, and a frame Vision of an improved temporary support for the structure indicated generally at 11. The draw free end of the draw bar structure. The invenbar frame structure includes a pair of channel tion consists in certain'features and elements of side members, 12, having inturned flanges, and construction, in combination, as herein shown and the yrearward ends of said membersare spaced 70 described, and as indicated by the claims. apart and rigidly secured by gusset plates, 13, In the drawings: to the front member, 14, of a swivel dolly. The Figure l is a plan view of a draw bar strucchannel side members, 12, converge forwardly,

ture embodying the present invention. with the extreme end portions, 12a,.bent in par- Figure 2 is a vertical longitudinal section taken allel, relatively close, spaced-apart relation, as 75 as indicated at line2-2 on Figure 1. seen in Figure l. These'end portions, 12a, of Figureis a vertical section through the lockthe side channels, are rigidly connected at top ing device taken at line 3-3 on Figure 1. kand bottom by plates, 16, which may be welded Figure 4 is a staggered horizontal sectional kin place, thus forming a support and guideview through the locking device, taken at line wayior the draw bar, 10, which is of substan- 80 4-4 on Figure 3. Y l tially rectangular, hollow formation. A pair of Figure 5 is a transverse section through the fortransversely extending truss members in the ward end of the draw bar, as indicated at line form of channels, 17, are secured to the flanges 5-5 on Figure 1. f of the side members, 12, intermediate their Figure 6 is a transverse view through lthe temlength. Welded to the inner surface of each 85 porary supporting leg, taken at line 6-6 on Figof the channel members, 17, as seen in Figure ure 2. 2, are plates, 12,3, for engaging the top and bot? The draw bar structure embodying this inventom surfacesl of the draw bar, l0, providing adtion is particularly adapted for use in connecditional support and guidance for the draw bar.

tion with trailer type road vehicles. Under the The draw bar structure, which is of hollow 90 laws in various territories, the permissible overformation, has an eyelet member, 20, for connec-y all length of tractor-trailer train combinations tion to a coupler of a draft vehicle, rigidly sehas been considerably restricted, necessitating the cured in its forward end in a suitable manner. use of shorter bodies on the trailer vehicles. In Rigidly secured on the top and bottom of said order to obtain maximum body capacity andstill draw bar member at the forward end are recome within the permissible over-all length of inforcing plates, 21, which are adapted to abut trailer train combination, itis desirable to reduce against the ends of the terminals, 12a, of the the space between vehiclesto the minimum, thus side members, 12, and serve as a stop for limitbringing the bodies in relatively close proX- ing the movement of the draw bar when teleimity to eachother, with just suicient clearscoped into the frame structure. And rigidlyll ance therebetween to permit turning corners. secured on top andbottorn ofthe rear end of Frequently, when tractor-trailer trains are in said draw bar are plates, 22, which are arranged use olf of the highways, the particular to abut against the transverse truss members, path to be traveled and frequently the special 17, to limit the extensibility of the draw bar in conditions imposed in loading and unloadingoi its frame, 11. the vehicles, necessitates such sharp turns, andl The draw bar may be adjustable in the frame the inclinations of the vehicle units with respect structure to' a plurality of positions for varying to each other may besuch that the corners of the its effective length,r andv for illustration the convbodies are apt to strike against-each other. struction disclosed permits of two positions of To avoid any damage resulting in such cases, the adjustment. Rigidly secured between the spacedapart trusses, 17, at one side of the draw bar is a channel clip, 24, and at the other side of the draw bar there is a housing bracket, 25, having a flat vertical surface, providing guidance for the draw bar against transverse movement. The housing is formed with a hollow cylindrical chamber, 26, extending in horizontal direction, in which is disposed a locking member or plunger, 27, arranged to be projected into either of two horizontally spaced apertures, 10a and 10b, formed in the adjacent side wall of the draw bar, 10, for locking the latter in fixed position with respect to the frame structure.

The cylindrical plunger, 27, is formed at the outer end with a recess, 27a, in which is disposed a compression spring, 28, reacting against the end wall of the chamber, 26, and normally urging the plunger toward the draw bar. A portion of the surface of the plunger is formed asa toothed rack, indicated at 27b with which meshes a spur pinion, 29, as seen in Figures 3 and 4. The spur pinion is also encased in the housing, 25, and its lower end is reduced, as inydicated at 29a, and journaled in the bearing plate, 251, secured to the bottom of the housing, 25. Rigidly secured to the lower end of the reduced portion, 23a, of said gear, by means of a key, 29h, is an operating handle, 3l, eX-

, tending laterally of the frame and held in place fon said portion, 29, by a machine screw, 30.

The housing, 25, is formed with a horizontally extending ange or shelf portion, a, in spaced relation to the bearing plate, 25h, between which are mounted detents in the form of levers, 33 and 34, carried on pivots, 35 and 36, respectively. The operating ends of these detent levers are urged toward each other by a spring, 37, bringing their eXtreme ends into contact with the Aperiphery of the lower portion of the spur gear member, 29. This lower surface of the spur gear just above the reduced portion, 29a, is cylindrical, as shown in the staggered section in Figure 4, and in this surface there is provided a pair of notches, 29c and 29d, with which the ends of the levers, 33 and 34, cooperate respectively, The lever, 34,is adapted to be engaged by a projection, 192, on the draw bar for automatically locking-the draw bar to the frame, as will presently be described. Secured to the inner wall of the tubular draw bar in registration with each of the apertures, 10e and 10b, for receiving the plunger, 27, are reinforcing bearing plates, 40, which are riveted in position so as to afford a substantial bearing face or abutment shoulder for engagement by the plunger. i

The operation of the lock device is as follows: In either position of longitudinal adjustment of the draw bar, l0, the operating lever, 3l, is in the position seen in Figure l of the drawings, with the plunger, 27, in locking engagement in one of the apertures, l0a or 10b, and the nose of the detent lever, 33, engaged with the stop shoulder of the notch, 29C. When it is desired to re- .lease the locking device to permit increasing or decreasing the eifective draw bar length, this trip lever, 33, is rst moved out of engagement with its stop shoulder, 29C, and the operating lever, 3l, is then swung counter-clockwise to the vposition seen in Figure 4; such movement of the Vlever causes rotation of the `spur gear, 29, and

withdraws the plunger, 27, from the aperture of the draw bar, against the reaction of its spring, 28, and in this position of adjustment of the parts the nose of the detent lever, 34, under the iniiuence of the spring, 37, engages the stop disposed shoulder of notch, 29d, of the spur gear', and thus locks the gear against return movement, and holds the plunger, 27, at inoperative position, as seen in Figure With the parts of the looking device in this position, the draw bar, 10, may be moved to either of its limits of adjustnient.

Assuming that the draw baris to be extended with respect to lthe position seen in VFigure l of the drawings, the outer end of the lever, 34, is in close proximity to the draw bar, so that as the bar isv pulled forwardly, the lug or projection, 10e, on its side, as seen in Figure 4,

will encounter the cam-shaped end portion of the lever, 34, and rock it outwardly so as to shift its nose out of engagement with the stop which time the spring, 28, forcibly projects saidV plunger into locking position for securing the draw bar to the frame structure. Such movement of the plunger causes rotation of the spur gear and its lever to normal position, in which position the nose of the lever, 33, is again caused to snap into engagement with the stop shoulder, 29C, under the influence of the spring, 37. It will also be clear that when it is desired to decrease the length of the draw bar, a similar cycle of operation is followed. That is, the tripA lever, 33, is first shifted out of locking position and the lever, 3l, rotated to retract the plunger, and the plunger is automatically locked in withdrawn position by the detent or trip lever, 34. Then, when the draw bar is moved rearwardly, the projection, 10G, on the draw bar, again engages the outer portion of the lever, 34, but from the opposite side, and again rocks it about its pivot, 36, shifting its nose out of engagement with the stop shoulder, 29d, thus releasing the spur gear and lever7 and placing the plunger under the influence of the spring, 28, so that it rides over the smooth surface of the draw bar until it registers with the aperture, 10b, into which it is forced by the spring in locking relation, rotating the spur gear and lever to normal position, with the trip latch, 33, engaging the stop shoulder, 29. positions of adjustment of the draw bar are required, the stops, 2l and 22, at the opposite ends of the draw bar, have a further advantage in that they serve to definitely limit its movement at positions of exact registration of the apertures and the plunger for locking action.

This particular construction has a decided advantage in that it is quick and positive in operation, and reduces the possibility of injury to the operator, because, after the trip, 33, and lever, 3l,k

have been manipulated, the operator may step clear of the vehicles so as to insure being out of the path of their wheels, and then the draft vehicle may be moved forward or backward to withdraw or return the draw bar to its other limit of movement, at which position it is automaticallydraw bar structure in proper position when thev It will be understood that when only two` iscY dolly is attached to the semi-trailer,` oreven when free. For this purpose there is shown a temporary supportingleg, which` is secured adjacent theforward or free end of the structure, substantially on thelongitudinal center. This temporary support includes a vertically extending screw, 45, rigidly secured by a bracket, 46, to the inner web of the lower channel truss member, 17. Surroundingthe screw is a housing or sleeve member, 47, the upperI end of which is formed for threaded engagement on the screw, and the lower end of which provides a bearing for the swivel bolt, 48, carrying the caster journal bracket, 49, of the caster wheel, 50.v The upper portion of the sleeve or housing, 46, is slotted, as seen in Figure 6, and on the opposite sides of the slot are laterally projecting lugs, 47a, which are connected by a clamping bolt, 52, having anhand-piece, 53, for conveniently rotating the bolt. It will be understood that the screw, 52, through the lugs, 47a,

serves to draw the lugs toward each other and thereby provides a friction grip on the threads of the screw, 45, for locking the sleeve and swivel Wheel at any position of adjustment. A hand wheel, 54, is rigidly secured to the sleeve approximately midway of its length, thus permitting convenient access for readily shifting the sleeve and its swivel wheel up or down.

While there is shown and described herein certain specic structure embodying this invention, it will be manifest to those skilled in thevart that various modifications and re-arrangements of the parts may be made without departing from the spirit and the scope of the invention, and that the 1 same is not limited to the particular form herein shown and described, except in so far as indicated by the appended claims.

We claim:

l. In 'combination,.a draw bar frame, a draur bar carried on the frame and longitudinally adjustable relative thereto, and automatic means for locking the draw bar to the frame in a plurality of positions of longitudinal adjustment, said means including a yieldingly actuated, manu- '1 ally releasable locking member, a detent for temporarily holding the locking member in releasing position, and means arranged to disengage the detent in response to longitudinal movement of said draw bar, for permitting said locking member to be moved automatically to locking position.

2. In combination, a draw bar frame, a draw bar carried on the frame and longitudinally adjustable relative thereto, and automatic means for locking the draw bar to the frame in a plurality of positions of longitudinal adjustment, said means including a yieldingly actuated, manually releasable locking member, a detent for temporarily holding the locking member in releasing position, means arranged to disengage the detent in response to longitudinal movement of said draw bar, for permitting said locking member to be moved automatically to locking position, and a yielding detent for positively holding said locking member in locking position.

3. In combination, adraw bar frame, a draw bar carried on the frame and longitudinally adjusted relative thereto, and automatic means for locking the draw bar to the frame in a plurality of positions orf longitudinali adjustment, said meansincluding a yieldingly actuated locking member, manually operable means arranged for withdrawing the locking member to release the A draw bar, a detent for temporarily holding said means and the locking member in releasing pober to be yieldingly urged to position for locking` the drawbar to the frame.

4. In combinatiorna draw bar frame, a draw bar carried on the frame and longitudinally ad-v justable relative thereto, and automatic means for-locking the draw bar to the frame in two positions of longitudinal adjustment, said means including a yieldingly actuated, manually movable looking member for locking the draw bar to the frame at either position of longitudinal adjustment, a detent for temporarily holding the locking member in releasing position when it has been moved to such position, and means arranged to disengage the detent, when the draw bar is moved toward its other position'of longitudinal adjustment, for releasing the locking member and permitting it to be yieldingly urged toward locking position. i

5. In combination, a draw bar frame structure, a draw bar carried on the frame and longitudinally adjustable relative thereto, and automatic means on the frame structure for locking the draw bar to the frame structure in a plurality of positions of longitudinal adjustment, said means including-a support, a manually withdrawable plunger carried by the support and engageable with abutment shoulders on the draw bar at each of lsaid positions of adjustment, a spring urging the plunger into such locking position, a detent on the support arranged for temporarily holding the plunger in withdrawn position, and a projection on the draw bar positioned to disengage the detent when said draw bar is longitudinally moved, for permitting said plunger to be yieldingly moved toward operative position.

6. In combination, a draw bar frame structure, a draw bar carried on the frame and lonand means positioned to: disengage saidA u gitudinally adjustable relative thereto, and automatic means on the frame structure for locking the draw bar tothe frame structure in a plurality of positions of longitudinal adjustment, said means including a support, a manually withdrawable plunger carried by the support and engageable in recesses of the draw bar which correspond to the respective positions of adjustment of said draw bar, the surface of the draw bar intermediate the recesses being smooth, Va spring yieldingly urging the plunger in locking direction, a detent on the support arranged for temporarily holding said plunger in Withdrawn position, and a projection on the draw bar positioned to encounter the detent in response to longitudinal movement of the draw bar, for releasing the plunger before another recess of the draw bar registers therewith, thus causing said plunger to yieldingly engage and ride against the smooth surface of the draw bar until a recess registers therewith.

7. In combination, a draw bar frame structure, a draw bar carried on the frame and longitudinally adjustable relative thereto, and automatic .means on the frame structure for locking' bar at each of said positions of adjustment, said plunger having its surface provided with a toothed rack, a gear carried on the support and meshing 1 C with said rack, an operating handle connected bar' adapted when saiddraw bar is longitudinally moved, to'release` said detent andY permit the plunger to be yieldinglyurged towardloclzrV ing position.

8. In the construction definedin claim- 7, a second detent carried on the supporty and positioned to automatically engage a stop shoulder on the gear' when the plunger has moved to locking position, for maintaining it in such posi-tion.

EDWIN H. ALLEN. GEORGE CONNORS. 

